They think it started as a DDEC2, then they changed engines and they believe its a DDEC3 now. There are no lights on. They have a loss of power, almost like its starting in 2nd gear, which it isnt. They mentioned possibly turbo or is there a sensor related? Maybe an injector? They have tried all basic things, filters, etc

Check to make sure he has the correct turbo boost sensor for the engine. It is different on a DDEC 11 to a DDEC 111. If it goes into smoke control while accelerating it will seem sluggish until the bus gets going. Cheers Gerry

But I do know if the coach was running OK and nobody screwed with it before it started exhibiting funny characteristics there are three things I would check. First would be the connectors. All connectors will tend to mess up the operation of a DDEC equipped engine if there is bad contacts or corrosion. Simply plugging or unplugging things a time or two makes a problem go away.

If that did not cure it I would verify the operation of the throttle position sensor and the operation of the turbo boost sensor, both of which I know can impact the engine power. Those have connectors also and would be on the list of ones to check.

Gee....I surely dont know and he probably wouldnt know. All that is know is that it ran fine until recently. It still runs fine and they drive it. Its just the off the line power loss and a slight vibration at cruising speed.I suggested Power Service because it had been sitting with a pretty empty tank for a couple months. I was thinking algea, water, bad fuel, etc.

I'm surely DDEC ignorant. In talking last night he mentioned "fixing" it once before by unplugging the main plug. He is going to try that again. I'm sure being in GA, that could be an issue.

I can tell you from personal experience that all of the above suggestions are good advice!

I have had the same experience with an 8V92 and the first time it turned out to be the fuses for the injectors. One bank firing and one not. Sounded like it was running fine at idle. But a sick dog on take off. Once up to speed it did sorta OK but still not right. Changed fuse holders no more problems. Ran bus 3 more yrs and sold it!

Second experience was coming home from NC and in the mountains it was a complete dog. On the open highway it'd make do, but still struggled with any hill, or trying to acceleration at all. And after pulling into a rest area to check it out w/no problems found it was a dog the rest of the way home.

After calling "The Don" he told me that he was pretty sure it was a bad boost sensor. Took the old one out, got the part # off it drove to Memphis and picked up a new one took it home, installed and test drove!